It is known as electrical penetrant structure (so called sealed lead-in) which transfers electric energy of a high voltage through hermetic cocoon of the atomic power station. This electrical penetrant structure has the hermetic case under gas pressure and bushing insulators which are welded to the case from two sides. The copper conductor is laid out through axial aperture of the insulators. The copper conductor consists of an integral copper core outside and flexible conducting elements inside of the penetrant structure. These elements compensate the thermal expansion of a conductor arising during passage of currents of short circuit or starting currents. Flexible electrical elements are attached to an integral copper core by the soldering or by the pressure jointing inside of tightly made and welded case and they are not controlled while in operation. Presence of uncontrollable contact connections inside of the penetrant structure is not allowed, since it carries out electric supply of the crucial equipment in containment of nuclear stations (see the U.S. Pat. No. 4,237,336, G21C 013/04, 1980).
The most similar design in technical essence is electrical penetrant structure (the patent of the U.S. Pat. No. 3,856,983, class G21C 013/04; H01B017/30, 1974), which is used for input of electrical energy in containment of nuclear stations. This electrical hermetic penetrant structure consists of the metal case under pressure of gas, bushing insulators attached to the case through thin-walled transitive details and through bellows, and a monolithic current conducting core with the firm insulation, tightly installed inside bushing insulators. The ends of a conductor run out from the case and they are sealed in bushing insulators, which are fixed on the case through the bellows (metal membranes) for providing the limited movements of a core in horizontal and vertical directions. The known design has U-shaped and crimped metal bellows, made of an alloy with low factor of temperature expansion. These bellows are soldered to ceramic insulator. Such alloys (phenyl, kovar, etc.) have moderate corrosion stability, but are subject to electrochemical corrosion.
Use of the specified alloys till now has been justified by rather low requirements to hermetic penetrant structure regarding service life and parameters of emergency operation (40 years, 150° C., 5 Bar).
At present time the design modes of an intensive irrigation of the penetrant structures by acids and alkalis are stipulated in containment of the atomic power stations. Such acids and alkalis work as initiators of electrochemical corrosion of the bellows and the thin-walled details connected to them since they are accumulated in open deepening of the corrugation and exposed to intensive influence of a powerful electromagnetic field around the penetrant structure.
Because of bellows have insignificant thickness they are destroyed at presence of the corrosion centers and electrical penetrant structure loses tightness.